Scientists spot the world’s biggest plant which is more than thrice the size of Manhattan Island

Written By Parul Sharma | Updated: Jun 02, 2022, 12:57 PM IST

Earth’s biggest plant - Posidonia australis covers about 200 sq km. Interestingly, it is largely sterile and is surviving despite not having sex.

The biggest plant anywhere on Earth belongs to a species called 'Posidonia australis'. It is commonly known as fibre-ball weed or ribbon weed and can be spotted along the southern coastlines of Australia.

According to scientists, this plant has sprung from a single seed, which was a merger of two different seagrass species about 4,500 years ago.

The Earth’s biggest plant covers about 200 sq km, which is more than three times the size of Manhattan Island.

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In depth research conducted to study the genetic differences in ribbon weed across Australia’s west coast – Shark Bay unveiled surprising outcomes. While the samples for this study were taken from plants growing 180km apart, there were no multiple specimens of the plant.

Scientists were surprised to spot the specimens of Posidonia australis so distant from one another until they realised that it was the same plant. Speaking about their response on realising that it’s a single plant, ecologist at Flinders University – Dr Martin Breed said, “We were completely stumped.”

According to student researcher from the University of Western Australia - Jen Edgeloe, “The existing 200 sq km of ribbon weed meadows appear to have expanded from a single, colonising seedling.” The same plant appears to have spread in a large are using the rhizomes just like a lawn spreads.

The plant has now become the habitat for many marine species, including dolphins, turtles, crabs and even fish.

As per the authors of the research, the plant must have taken 4,500 years to expand this far. This has been derived post analysing the growth speed of ribbon weed rhizomes which grow about 35cm a year.

Interestingly, the plant is thriving despite the challenging conditions in Shark Bay. It is able to survive in parts where the salinity is twice as anywhere in the region.

The seagrass plant’s survival might be connected to its absorption of varied chromosomes from its two parents.

“Instead of getting half [of] its genes from mum and half from dad, it’s kept all of them”, said Ben.

While the team is still researching about the giant plant, Ben says that it seems to be “largely sterile”. This implies that the plant has to rely on its own for survival.

As the plant ‘doesn’t have sex’, its survival for such a long time is quite surprising. This is because such plants usually have a reduced genetic diversity, which is needed to tackle environmental changes.

Often addressed as the world’s largest plant, the Shark Bay ribbon weed is much larger than the Aspen trees in Utah which cover 43 hectares.